From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=BAYES_00,INVALID_DATE autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,8264dac98bc604d8 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 1993-03-18 09:54:59 PST Newsgroups: comp.lang.ada Path: sparky!uunet!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!att!att-out!cbnewsl!willett From: willett@cbnewsl.cb.att.com (david.c.willett) Subject: Re: The actual quote from the Post AAS article Organization: AT&T Bell Laboratories Date: Thu, 18 Mar 1993 17:49:15 GMT Message-ID: <1993Mar18.174915.11339@cbnewsl.cb.att.com> References: Date: 1993-03-18T17:49:15+00:00 List-Id: >From article , by srctran@world.std.com (Gregory Aharonian): > >>It seems to me that the complexity of an ATC system would increase similarly >>to the N-body problem from physics. An example of such a problem is to >>predict the motion of an electron travelling through a distribution of >>charges. If memory serves, that problem is O(X**n) where N is the number >>of charges and X is the number of electrons. > > N-body problems in physics, under many conditions, can be numerically > handle without the combinatoric explosion of calculations due to > interparticle forces (for example, gravitational problems can be simplified > for cluster like problems using trees where the nodes are center-of-masses, > while electrical problems like in quantum mechanics can be simpligfied > using generalized potentials). > Unfortuantely, none of these procedures works with planes, so that there > is little analogy to be made. > > Greg Aharonian > Source Translation & Optimization > -- > ************************************************************************** > Greg Aharonian > Source Translation & Optimiztion > P.O. Box 404, Belmont, MA 02178 The simplifications you describe depend on the relative positions and densities of the masses involved. I think the analogy is apt. -- Dave Willett AT&T Federal Systems Advanced Technologies A Theoretical Physicist is one whose existence is postulated to make the numbers balance, but is never observed in the laboratory.